Optimal power allocation for relay assisted F/TDMA ad hoc networks

In this paper, we study the power allocation problem at the relay nodes for two-hop F/TDMA networks with multiple sources and destinations. Considering the sum capacity as the performance metric, we solve the problem of optimally allocating the total power of each relay node between the transmissions it is assisting. We consider regenerative decode-and-forward (RDF), nonregenerative decode-and-forward (NDF), amplify-and-forward (AF) and compress-and-forward (CF) at the relay nodes. We observe that the optimum power allocation for the RDF and NDF cases are modified water-filling solutions. In RDF, the optimum power allocation considers both the direct links of the users and the relay to destination links, whereas the optimal power allocation for the NDF relaying considers only the relay to destination links. We also observe that relay nodes employing AF or CF may provide higher sum capacities than relay nodes employing DF techniques when sufficient power is available at the relay nodes. Motivated by the optimum power allocation identified for each case, we provide insights to relay selection strategies for relay assisted F/TDMA networks.

[1]  Michael Gastpar,et al.  Cooperative strategies and capacity theorems for relay networks , 2005, IEEE Transactions on Information Theory.

[2]  Panganamala Ramana Kumar,et al.  Towards an information theory of large networks: an achievable rate region , 2003, IEEE Trans. Inf. Theory.

[3]  Aaron D. Wyner,et al.  The rate-distortion function for source coding with side information at the decoder , 1976, IEEE Trans. Inf. Theory.

[4]  J. Wolfowitz.  The rate distortion function for source coding with side information at the decoder , 1979 .

[5]  D.R. Brown,et al.  Resource allocation for cooperative transmission in wireless networks with orthogonal users , 2004, Conference Record of the Thirty-Eighth Asilomar Conference on Signals, Systems and Computers, 2004..

[6]  Elza Erkip,et al.  User cooperation diversity. Part I. System description , 2003, IEEE Trans. Commun..

[7]  Roy D. Yates,et al.  Forwarding strategies for Gaussian parallel-relay networks , 2004, International Symposium onInformation Theory, 2004. ISIT 2004. Proceedings..

[8]  Junshan Zhang,et al.  Capacity Bounds and Power Allocation for the Wireless Relay Channel , 1990 .

[9]  Abbas El Gamal,et al.  Capacity theorems for the relay channel , 1979, IEEE Trans. Inf. Theory.

[10]  Anders Høst-Madsen,et al.  Capacity bounds and power allocation for wireless relay channels , 2005, IEEE Transactions on Information Theory.

[11]  Mazen O. Hasna,et al.  Optimal power allocation for relayed transmissions over Rayleigh-fading channels , 2004, IEEE Transactions on Wireless Communications.

[12]  Gregory W. Wornell,et al.  Cooperative diversity in wireless networks: Efficient protocols and outage behavior , 2004, IEEE Transactions on Information Theory.